Data processing apparatus

ABSTRACT

A data processing apparatus has a first processing unit for processing an input data, a second processing unit responsive to the data processed by the first processing unit for executing a processing dependent on the data and producing a display data, and a display unit having a display drive unit and a display device for displaying the display data. The second processing unit is selectively inactivated and activated under control of the first processing unit to reduce power consumption in the second processing unit. The display drive unit is also selectively inactivated and activated under control of the first processing unit to reduce power consumption in the display unit. The display device has a memory function that maintains its display image even when supply of a display drive signal from the display drive unit is stopped, so that a latest image before inactivation of the second processing unit and/or the display drive unit for power consumption reduction is visible by an operator during the inactivated and low power consumption state of the apparatus.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a data processing apparatusprovided with a display device.

[0003] 2. Description of the Prior Art

[0004] Among microcomputers which become compact in size and reduced inweight, portable type computers powered by batteries have overwhelminglyprevailed these days. Particularly, one of them known as a note-sizecomputer is lighter in weight and smaller in size yet providing equalcapabilities to those of a desktop or laptop computer. The note-sizecomputer powered by batteries is handy for use in a place where powersupply facility is rarely available, e.g. a meeting room or a lecturehall.

[0005] However, the disadvantage in such handy use is that the life ofbatteries is short and limited. When using for record of a businessmeeting or a college lecture, the service duration of such a note-sizecomputer with fully charged batteries is preferably 10 hours in nonstop;more preferably, 20 to 30 hours. If possible, more than 100 hours-astandard of hand calculators-is most desired.

[0006] So far, the service operation of a commercially availablenote-size computer lasts 2 to 3 hours at best. This results in batteryrunout in the middle of a meeting or college lecture causing aninterruption during input work. As a result, troublesome replacement ofbatteries with new ones will be needed at considerable frequency.

[0007] Such a drawback of the note-size computer tends to offset theportability in spite of its light weight and compactness.

[0008] It is understood that known pocket-type portable data processingapparatuses including hand calculators and electronic notebooks are muchslower in processing speeds than common microcomputers and thus, exhibitless power requirements. They are capable of servicing for years withthe use of a common primary cell(s) of which life will thus be no matterof concern. The note-size computer is however as high a processing speedas of a desktop computer and consumes a considerable amount of electricenergy-namely, 10 to 1000 times the power consumption of any pocket-typeportable data processing apparatus. Even with the application ofup-to-date high quality rechargeable batteries, the serving period willbe 2 to 3 hours at maximum. This is far from a desired duration demandedby the users. For the purpose of compensating the short life ofbatteries, numbers of techniques for energy saving has been developedand some are now in practical use.

[0009] A most known art will then be explained.

[0010] That is called “resume” function which is widely used in a commonnote-size computer. It works in a manner that when no input actioncontinues for a given period of time, the data needed for restarting thecomputer with corresponding information is saved in a nonvolatile ICmemory and then, a CPU and a display are systematically turned off. Forrestart, a power switch is closed and the data stored in the IC memoryis instantly retrieved for display of the preceding data provided beforedisconnection of the power supply. This technique is effective forextension of the battery servicing time and suitable in practical use.

[0011] However, a specified duration, e.g. 5 minutes, of no key entryresults in de-energization of the entire system of the computer andthus, disappearance of display data. Accordingly, the operator losesinformation and his input action is interrupted. For reviewing thedisplay data or continuing the input action, the power switch has to beturned on each time. This is a very nuisance procedure for the operator.The resume technique is advantageous in saving energy of battery powerbut very disadvantageous in operability of the note-size computer.

[0012] More specifically, the foregoing technique incorporates as ameans for energy saving a system which de-energizes all the componentsincluding a processing circuit and a display circuit. The operator isthus requested to turn on the power switch of the computer atconsiderable frequencies during intermittent data input action becauseeach no data entry duration of a given length triggers automaticdisconnection of the switch. In particular, data input operation with anote-size computer is commonly intermittent and thus, the foregoingdisadvantage will be much emphasized.

SUMMARY OF THE INVENTION

[0013] It is an object of the present invention, in view of solution ofthe above disadvantage, to provide an improved data processing apparatuscapable of remarkably reducing power consumption while performingrequired data processing operations.

[0014] A data processing apparatus according to the present inventioncomprises: a data input unit for input of external data; a firstprocessing unit for processing the data inputted through the data inputunit; a second processing unit for processing the data inputted throughthe data input unit and/or an output data of the first processing unit;and a display unit for displaying an output data of the first and/orsecond processing units, wherein the display unit has a memory functionfor keeping a display state without being energized, and the firstprocessing unit has a means for actuating the second processing unitaccording to a timing or a kind of the input data.

[0015] For example, when no data entry continues, the second processingunit or the display unit is inactivated or decreased in clock rate thusdiminishing power consumption. Also, the present invention allows thedisplay of data to remain intact. Upon occurrence an input data, thefirst processing unit activates the second processing unit to processthe data. Thus, the operator can prosecute his job without knowing aninterrupted de-energization. As the result, an appreciable degree ofenergy saving is guaranteed without affecting the operability and thus,the service life of batteries will largely be increased.

[0016] In another aspect, the first processing unit may activate thesecond processing unit according to the kind of the input data. When theinput data is such a data that requires a processing in the secondprocessing unit, the first processing unit activates the secondprocessing unit. The second processing unit, after completing a requiredoperation or processing, may becomes an inactive state by itself or maybe forced into the inactive state by the first processing unit. Thus,the power consumption will be reduced to a considerable rate withoutaffecting the operability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a block diagram of a data processing apparatus showing afirst embodiment of the present invention;

[0018]FIG. 2 is a timing chart;

[0019]FIG. 3 is a view showing the arrangement of a display unit;

[0020]FIG. 4 is a cross sectional view explaining the operatingprinciple of the display unit;

[0021]FIG. 5 is a view showing displayed images on the display unit;

[0022]FIG. 6 is a flow chart;

[0023]FIG. 7-a is a block diagram showing an arrangement of components;

[0024]FIG. 7-b is a block diagram showing another arrangement;

[0025]FIG. 7-c is a block diagram showing a further arrangement;

[0026]FIG. 7-d is a flow chart;

[0027]FIG. 8 illustrates the operating principle of a reflective devicewith the use of different reflecting plates;

[0028]FIG. 9 is a block diagram showing a second embodiment of thepresent invention;

[0029]FIG. 10-a is a block diagram associated with a first processingunit;

[0030]FIG. 10-b is a block diagram associated with a second processingunit;

[0031] FIGS. 11-a and 11-b are flow charts:

[0032]FIG. 12 is a timing chart;

[0033]FIG. 13 is a view explaining the representation of a cursor;

[0034]FIG. 14 is a view showing a sequence of translation procedures;

[0035]FIG. 15 is a view explaining data insertion;

[0036]FIG. 16 is a view explaining a copy mode;

[0037]FIG. 17 is a block diagram showing a modification of the secondembodiment;

[0038]FIG. 18 is a block diagram showing a third embodiment of thepresent invention;

[0039]FIG. 19 is a flow chart;

[0040]FIG. 20 is a block diagram showing a fourth embodiment of thepresent invention;

[0041]FIG. 21 is a timing chart of the fourth embodiment;

[0042]FIG. 22 is a block diagram showing a fifth embodiment of thepresent invention;

[0043]FIG. 23 is a timing chart of the fifth embodiment;

[0044]FIG. 24 is a block diagram showing a data input unit; and

[0045]FIG. 25 is a block diagram showing a combination of the first andsecond processing units.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] Preferred embodiments of the present invention will be describedreferring to the accompanying drawings.

[0047] Embodiment 1

[0048]FIG. 1 is a block diagram of a data processing apparatus showing.a first embodiment of the present invention.

[0049] The data processing apparatus comprises a data input unit 3, afirst processing block 1, a second processing block 98, and a displayblock 99.

[0050] In operation, a data input which is fed to the data input unit 3of the data processing apparatus by means of key entry with a key-boardor communications interface is transferred to the first processing block1 in which a first processor 4 examines which key in key entry ispressed or what sorts of data are input from the outside and determinesthe following procedure according to the information from a first memory5.

[0051] If no input is supplied to the data input unit 3 throughout agiven period of time as shown in FIG. 2-a and also, the action of asecond processor 7 has been completed, the feeding of clock signals tothe second processor 7 and a display circuit 8 is halted by aninterruption controller 6 and/or a process of energy saving issystematically executed.

[0052] The energy saving process will now be described referring to FIG.2.

[0053] As shown in FIG. 2-a, a data input entered at t₁ using an n-thkey of the key-board is transferred from the data input unit 3 to the,first processor 4.

[0054] The first processor 4 when examining the data input anddetermining that further processing at the second processor 7 is neededdelivers a start instruction via the interruption controller 6 and astart instruction line 80 to the second processor 7 which thus commencesreceiving the data input from the first processor 4. The secondprocessor 7 starts processing the data input when t=t₃ as shown in FIG.2-c and upon finishing, sends an end signal to the first processor 4. Inturn, either the first processor 4 or the interruption controller 6delivers a stop instruction to the second processor 4 via the startupinstruction line 80. Accordingly, the second processor 4 transfersfinally processed data from its RAM memory or register to the secondmemory for temporary storage and then, stops processing action when t=t₅as shown in FIG. 2-c or enters into an energy saving mode where aconsuming power is sharply attenuated. After t₅ where the actuation ofthe second processor 7 is ceased, the data remains held in the secondmemory 9 due to its nonvolatile properties or because of action of aback-up battery. If display change is needed, the second processor 4sends a display change signal to the first processor 4. The firstprocessor 4 then delivers a display start instruction via a displaystart instruction line 81 to the display circuit 8 for startingactuation. When t=t₄ as shown in FIG. 2-d, the command signal istransmitted to the display circuit 8 which in turn retrieves the data ofa previous display text from a video memory 82 or the second memory 9and displays a new image corresponding to the display change signal anddata from the second processor 7. When t=t₆, the display circuit 8 sendsits own instruction or an end signal via the interruption controller 6to the first processor 4 and upon receiving an instruction from thefirst processor 4, stops or diminishes clock generation to enter adisplay energy saving mode. Thereafter, the power consumption of thedisplay circuit 8 will largely be declined as illustrated in after t₆ inFIG. 2-d.

[0055] After t₆, the display circuit 8 stays fully or nearly inactivatedbut a display 2 which is substantially consisted of memory retainabledevices, e.g. ferroelectric liquid crystal devices, continues to holdthe display image. The arrangement of the display 2 will then bedescribed. The display 2, e.g. a simple matrix type liquid crystaldisplay, contains a matrix of electrodes in which horizontal drive lines13 and vertical drive lines 14 coupled to a horizontal driver 11 and avertical driver 12 respectively intersect each other, as best shown inFIG. 3. FIG. 4 illustrates a pixel of the display 2 in action with avoltage being applied.

[0056] In each pixel, a ferroelectric liquid crystal 17 is energized bythe two, horizontal and vertical lines 13, 14 which serve as electrodesand are provided on a glass plates 15 and 16 respectively.

[0057] More particularly, FIG. 4-a shows a state where light istransmitted through. When a signal is given, the ferroelectric liquidcrystal 17 changes its crystalline orientation and acts as a polarizerin which an angle of polarization is altered, thus allowing the light topass through.

[0058] When a voltage is applied in the reverse direction, theferroelectric liquid crystal 17 causes the angle of polarization to turn90 degrees and inhibits the light to pass with polarization effects, asshown in FIG. 4-b. The ferroelectric liquid crystal 17 also has a memoryretainable effect as being capable of remaining unchanged in thecrystalline orientation after the supply of voltage is stopped, as shownin FIG. 4-c. Accordingly, throughout a duration from t=t₆ to t=t₁₄,explained later, the display remains intact without any operation of thedisplay circuit 8. While the energy saving mode is involved after t₆,both the data input unit 3 and the first processor 4 are only in action.

[0059] The first processor 4 performs only conversion of key entry toletter code or the like. In general, the key entry is conducted by ahuman operator and executed some tens times in a second at best. Thespeed of data entry by a human operator is 100 times or more slower thanthe processing speed of any microcomputer. Hence, the processing speedof the first processor 4 may be as low as of a known hand calculator andthe power consumption will be decreased to hundredths or thousandths ofone watt as compared with that of a main CPU in a desktop computer. Asshown in FIG. 2-b, the first processor 4 continues operating while apower switch 20 of the data processing unit 1 is closed. However, itconsumes less amounts of energy and thus, the power consumption of theapparatus will be low.

[0060] When n+l-th key entry is made at t₁₁, the first processor 4examines the data of the entry at t₁₂ and if necessary, delivers a startinstruction via the interruption controller 6 or directly to the secondprocessor 7 for actuation. Upon receiving the start instruction, thesecond processor 7 starts processing again with the use of clock signalsso that the data stored in the second memory 9, i.e. data at a previousstop when t=t₅, such as memory data, register information, or displaydata, is read out and the CPU environment when t=t₅ can fully berestored. When t=t₁₃, the data in the first processor 4 is transferredto the second processor 7 for reprocessing. The second processor 7 isarranged to operate at high speeds and its power consumption is as highas that of a desk-top computer. If the second processor 7 iscontinuously activated, the life of batteries will be shortened as wellas in a known note computer. The present invention however provides aseries of energy saving mode actions during the operation, whereby theenergy consumption will be minimized.

[0061] The energy saving mode is advantageous. For example, the durationrequired for processing the data of a word processing software iscommonly less than 1 ms while the key entry by a human operator takesseveral tens of milliseconds at maximum. Hence, although the peak ofenergy consumption during a period from t₁₃ to t₁₅ is fairly high in thesecond processor 7 as shown in FIG. 2-c, the average is not more than atenth or a hundredth of the peak value. It is now understood that theenergy saving mode allows lower power consumption.

[0062] When t=t₁₄, the second processor 7 sends a desired portion of thedisplay data to the display 2. Before t₁₄, the display 2 continues todisplay the text altered at t₆ due to the memory effects of theferroelectric liquid crystal 17 while the display circuit 8 remainsinactivated. The desired data given through the key entry at t₁₁ iswritten at t₁₄ for regional replacement. The replacement of one toseveral lines of display text is executed by means of voltageapplication to corresponding numbers of the horizontal and verticaldrive lines 13 and 14. This procedure requires a shorter period ofprocessing time and thus, consumes a less amount of energy as comparedwith replacement of the entire display text.

[0063] The second processor 7 then stops operation when t=t₁₅ and entersinto the energy saving mode again as shown in FIG. 2-c.

[0064] At the moment when the operation of the second processor 7 hasbeen finished before t₁₅ or when a stop instruction from the firstprocessor 4 is received, the second processor 7 saves the latest data inthe second memory 9.

[0065] When t=t₁₄, the second processor 7 stops operation or diminishesan operating speed and enters into the energy saving mode.

[0066] When the input data is fed at short intervals, e.g. at t₂₁, t₃₁,t_(4l), and t₁₅, through a series of key entry actions or from acommunications port, the second processor 7 shifts to the energy savingmode at t₂₃, t₃₃, and t₄₃ as shown in FIG. 2-c. If the first processor 4detects that the interval between data inputs is shorter than apredetermined time, it delivers an energy saving mode stop instructionto the second processor 7 which thus remains activated without forcedde-energization and no more enters into the energy saving mode. Theenergy saving mode is called back only when the interval between twodata inputs becomes longer enough.

[0067] Also, when the first processor 4 detects that the key entry isabsent during a given length of time, it actuates to disconnect thepower supply to primary components including the first processor 4 forshift to a power supply stop mode. The memory data is being saved by theback-up battery while the power supply is fully disconnected.

[0068] Before disconnection of the power supply, the first processor 2however sends a power supply stop display instruction directly or viathe second processor 7 to the display circuit 8 for display of an “OFF”sign 21 shown in FIG. 5-b and then, enters into the power supply stopmode. The OFF sign 21 remains displayed due to the memory effects of thedisplay 2 after the power supply is disconnected, thus allowing theoperator to distinguish the power supply stop mode from the energysaving mode.

[0069] In the energy saving mode, the operation can be started again bykey entry action and thus, the operator will perceive no interruption inthe processing action.

[0070] In the power supply stop mode, the OFF sign 21 is displayed andthe operator can restart the operation in succession with the previousdata retrieved from the second memory 9 by the second processor 9 whenthe power switch 20 is turned on. This procedure is similar to that inthe conventional “resume” mode.

[0071] The foregoing operation will now be described in mode detailreferring to a flow chart of FIG. 6. When the power switch 20 is turnedon at Step 101, the first processor 4 starts activating at Step 102. Theinput data given by key entry is transferred from the data input unit 3to the first processor 4 at Step 103. At Step 104, it is examinedwhether the duration of no-data entry lasts for a predetermined time ornot. If the no-data entry duration t is greater than the predeterminedtime, the procedure moves to Step 105 where the actuation of the secondprocessor 7 is examined. If the second processor 7 is in action, theprocedure moves back to Step 103. If not, the entire apparatus isde-energized, at Step 106, and stops actuating at Step 107 beforerestarting with Step 101 where the power supply switch 20 is closed.

[0072] If the no-data entry duration t is greater but as short as a fewminutes, the procedure is shifted from Step 104 to Step 108. When theprocessing frequency in the first and second processors 4 and 7 is low,the procedure moves from Step 108 to Step 109 where a back light isturned off for energy saving.

[0073] If the no-data entry duration t is not greater, the operation inthe first processor 4 is prosecuted at Step 110. Also, it is examined atStep 110 a whether the data of text is kept displayed throughout aconsiderable length of time or not. If too long, refreshing action ofthe data display is executed at Step 110 b for prevention of an imageburn on the screen. At Step 110 c, the processing frequency in thesecond processor 7 is examined and if it is high, the second processor 7is kept in action at Step 110 d. If the processing frequency is low, theprocedure moves to Step 111. When it is determined at Step 111 that nofurther processing in the second processor 7 is needed, the procedurereturns to Step 103.

[0074] When further processing in the second processor 7 is required,the procedure moves from Step 111 to Step 112 a where the actuation ofthe second processor 7 is examined. If the second processor 7 is not inaction, a start instruction is fed at Step 112 b to the second processor7 which is in turn activated at Step 113 by the first processor 4 andthe interruption controller 6. The second processor 7 then startsprocessing action at Step 114. If it is determined at Step 115 that achange in the text of display is needed, the procedure moves to Step 116a where a display change instruction is supplied to both theinterruption controller 6 and the first processor 4. Then, theinterruption controller 6 delivers a display energizing instruction tothe display block 99 at Step 116 b. The display circuit 8 is. activatedat Step 116 c and the display change on the display 2 including thereplacement of a regional data with a desired data is carried out atStep 117. After the display change is checked at Step 118, a displaychange completion signal is sent to the first processor 4 at Step 117 a.When the display change completion signal is accepted at Step 117 b, thedisplay 2 is turned off at Step 119.

[0075] If no change in the display text is needed, the procedure movesfrom Step 115 to Step 120 where the completion of the processing in thesecond processor 7 is examined. If yes, a processing completion signalis released at Step 120 a. As the result, the second processor 7 stopsoperation at Step 121 upon receiving a stop signal produced at Step 120b and the procedure returns back to Step 103.

[0076] FIGS. 7-a and 7-b are block diagrams of a note-size computeraccording to the first embodiment of the present invention.

[0077] As shown in FIG. 7-a, a data input block 97 comprises a keyboard201, a communication port 51 with RS232C, and a floppy disk controller202. Also, a hard disk unit 203 is provided separately. A firstprocessing block 1 is mainly consisted of a first processor 4. A secondprocessing block 98 contains a second processor 7 which is a CPUarranged for shift to and back from the energy saving mode upon stoppingand feeding of a clock signal respectively and is coupled to a bus line210. Also, a ROM 204 for start action, a second memory 9 of DRAM, and abackup RAM 205 which is an SRAM for storage of individual data ofreturning from the resume mode are coupled to the bus line 210. Bothends of the bus line 210 are connected to the first processor 4 and adisplay block 99 respectively. The display block 99 has a graphiccontroller 206 and a liquid crystal controller driver 207 arranged in adisplay circuit. There are also provided a video RAM 209 and a liquidcrystal display 208. For energy saving operation, correspondingcomponents only in the arrangement are activated while the remainingcomponents are de-energized. This energy saving technique is illustratedin more detail in Table 1. In general, input operation for e.g. wordprocessing involves an intermittent action of keyboard entry. Hence, thepower supply is connected to every component except the communicationsI/O unit. While a clock signal is fed to the first processing block 1,no clock signals are supplied to the second processing block 98 and thedisplay block 99. Power is thus consumed only in the first processingblock 1. If necessary, the second block 98 and/or the display block 99are activated within a short period of time. If more frequent operationsare needed, the second processing block 98 is kept activated foracceleration of processing speeds.

[0078] When the key entry is absent for a given time, the secondprocessing block 98 is disconnected and simultaneously, its processingdata is stored in a backup memory for retrieval in response to thefollowing key entry.

[0079]FIG. 7-b is similar to FIG. 7-a, except that the first processor 4having a lower clock frequency is used as a “monitor” for the totalsystem and the processing will be executed by the second processor 7having a higher clock frequency. The first processor 4 is adapted foroperating an event processing method by which the second processor 7 isactivated for processing action corresponding to data of the keyboardentry. The second processor 7 stops operation for the purpose of energysaving when the processing action is finished and remains inactivateduntil another key entry commences. The display block 99 starts operatingin response to a display signal from the second processor 7 and stopsautomatically after completion of display. This procedure can beexecuted with a common operating system similar to any known operatingsystem, thus ensuring high software compatibility. For example, MS-DOSis designed to run with the use of one complete CPU. Hence, the energysaving effect will hardly be expected during operation with conventionalapplication software programs. It is then a good idea that a specificoperating system and a corresponding word processing software which areinstalled in two CPUs are provided in addition to the conventionaloperating system. Accordingly, word processing job can be performedusing the specific software with the operating system of the presentinvention and thus, the power consumption will be reduced to less than atenth or hundredth. Also, general purpose software programs can workwith the conventional operating system-although the energy saving effectwill be diminished. It would be understood that about 80% of the job ona note-size computer is word processing and the foregoing arrangementcan contribute to the energy saving.

[0080]FIG. 7-c is a block diagram of another example according to thefirst embodiment and FIG. 7-d is a flow chart showing a procedure withthe use of a conventional operating system such as MS-DOS. The secondprocessor 7 is a CPU capable of holding data from its register andinternal RAM during actuation of no clock or de-energization. When keyentry is made at Step 251, a keyboard code signal from the keyboard 201is transferred by the first processor 4 to a start device 221 whichremains activated, at Step 252. At Step 253, the start device 221delivers a clock signal to a main processor 222 which is de-energized.Both of the register 224 and the internal RAM 223 are coupled to abackup source and thus, start operating upon receipt of the clocksignal. At Step 254, the main processor 222 starts the program which hasbeen on stand-by for key entry. The program is then processed for e.g.word processing according to data of the key entry, at Step 255. At Step257, a display instruction is released for replacement of display textif required at Step 256. At Step 258, the graphic controller 206 isactivated. The data in the video RAM 209 is thus rewritten at Step 259.After the liquid crystal controller driver 207 is activated at Step 261,a desired change in the display text is made on the liquid crystaldisplay 208 formed of ferroelectric liquid crystal. Then, the video RAM209 is backup energized at Step 262 and the display block 99 isde-energized, at Step 263, thus entering into the energy saving mode.When the processing in the second processor 7 is completed at Step 270,the program stops and moves into a “keyboard entry stand-by” stage atStep 271. At Step 272, the data required for re-actuation of theregister 223 and the internal RAM 234 is saved and the second memory 9is backup energized before a clock in the CPU is stopped. Then, thesecond processor 7 stops operation, at Step 273, thus entering into theenergy saving mode. As the start device 221 remains activated, thesecond processor 7 stays on stand-by for input through keyboard entry atStep 251 or from the communications port 5. As understood, the startdevice 221 only is kept activated in the second processing block 98. TheCPU shown in FIG. 7-c provides backup of registers with its clockunactuated and ensures instant return to operation upon actuation of theclock. As a single unit of the CPU is commonly activated, a conventionaloperating system can be used with equal success. Also, existing softwareprograms including word processing programs can be processed with lessassignment and thus, private data stock will be permitted for optimumuse. Consequently, it would be apparent that this method is eligible. Inaddition, the consumption of electric energy will be much decreasedusing a technique of direct control of the first processor 1 on displaytext change which will be described later with a second embodiment ofthe present invention. As understood, the resume mode allows mostcomponents to remain de-energized when no keyboard entry lasts long.

[0081] As a ferroelectric liquid crystal material has a memory effect,permanent memory results known as protracted metastable phenomenon willappear when the same text is displayed for a longer time. For preventionof such phenomenon, a display change instruction is given to the firstprocessor 4 and the power switch 20 upon detection with the timer 22that the display duration exceeds a predetermined time in the energysaving mode or power supply stop mode. Accordingly, the display circuit8 actuates the display 2 to change the whole or a part of the displaytext, whereby permanent memory drawbacks will be eliminated.

[0082] If it is happened that the persistence of such permanent memoryeffects allows no change in the display text on the display 2, thecrystalline orientation of liquid crystal is realigned by heating up thedisplay 2 with a heater 24 triggered by a display reset switch 23. Then,arbitrary change in the display text on the display 2 will be possible.

[0083] Energy saving can be promoted by stopping the clock in the secondprocessor 7 during the energy saving mode. When more or full energysaving is wanted, the power supply to the second processor 7 or thedisplay circuit 8 is disconnected by the interruption controller 6.

[0084] As understood, the power supply stop mode requires a minimum ofpower consumption for backup of the second memory 9.

[0085] As shown in FIG. 1, the back light 25 is turned off when thepower source is a battery and a reflective device 27 is activated by areflection circuit 26 for display with a reflection mode.

[0086] The reflective device 27 is consisted of a film of ferroelectricliquid crystal which provides a transparent mode for transmission oflight, as shown in FIG. 8-a, and an opaque mode for reflection as shownin FIG. 8-b, for alternative action. Incoming light 32 is reflected onthe reflective device 27 and runs back as reflected light 33. At thetime, polarization is also effected by the polarizers in the display 2and the reflective device 27, whereby the number of components will bereduced, Also, a film-form electrochromic display device may be used forproviding a transmission mode and a white diffusion screen mode in whichit appears like a sheet of white paper.

[0087] The reflective device 27 may be of fixed type, as shown in FIGS.8-c and 8-d, comprising a light transmitting layer consisted of lowrefraction transmitting regions 28 and high refraction transmittingregions 29 and a reflecting layer 31 having apertures 30 therein.

[0088] As shown in FIG. 8-c, light emitted from the back light 25 entersthe high refraction transmitting regions 29 where it is fully reflectedon the interface between the high and low refraction transmittingregions 29, 28 and passes across the apertures 31 to a polarizer plate35. The polarized light is then transmitted to a liquid crystal layer 17for producing optical display with outwardly emitted light.

[0089] During the reflection mode in battery operation, outside light 32passes the liquid crystal layer 17 and is reflected by the reflectinglayer 31 formed by vapor deposition of aluminum and reflected light 33runs across the liquid crystal layer 17 again for providing opticaldisplay.

[0090] The reflective device 27 requires no external drive circuit, thuscontributing to the simple arrangement of a total system. It is knownthat such a combination of high and low refraction transmitting regionsis easily fabricated by a fused salt immersion method which is commonlyused for making refraction distributed lenses.

[0091] Although such a transmission/reflection combination type liquidcrystal display is disadvantageous in the quality of a display image ascompared with a transmission or reflection speciality type liquidcrystal display, the foregoing switching between transmission andreflection allows display of as good an image as of the speciality typedisplay in both the transmission and reflection modes. This technique isthus suited to two-source, battery and AC supply, drive application.

[0092] When the external power source is connected, the back light 25 islit upon receiving an instruction from the first processor 4 which alsodelivers a transmission instruction to the reflection circuit 26 andthus, the reflective device 27 becomes transparent simultaneously.Accordingly, transmitting light can illuminate the display as shown inFIG. 8a.

[0093] When the battery is connected, the first processor 4 delivers areflection signal to the reflection circuit 26 and the reflective device27 becomes opaque to cause reflection and diffusion. As the result, thedisplay is made by reflected outside light as shown in FIG. 8-b while anamount of electric energy required for actuation of the back light 25 issaved.

[0094] Also, the same result as shown in FIGS. 8-c and 8-d may beprovided with the use of a transmitting reflective plate 34 which isformed of a metal plate, e.g. of aluminum, having a multiplicity oftapered round apertures therein, as illustrated in FIGS. 8-e and 8-f.

[0095] As set forth above, the CPU in this arrangement providesintermittent actuation in response to the intermittent key entry and theaverage power consumption of the apparatus will be declined to anappreciable rate.

[0096] Also, the text remains on display during the operation and thus,the operator can perceive no sign of abnormality when the processingunit is inactivated. More particularly, a great degree of energy savingwill be ensured without affecting the operability.

[0097] In more particular, each key entry action takes several tens ofmilliseconds while the average of CPU processing durations in wordprocessing is about tens to hundreds of microseconds. Hence, the CPU isactivated {fraction (1/100)} to {fraction (1/1000)} of the key entryaction time for accomplishing the task and its energy consumption willthus be reduced in proportion. However, while the energy consumption ofthe CPU is reduced to {fraction (1/1000)}, {fraction (1/10)} to{fraction (1/20)} of the overall consumption remains intact because thedisplay unit consumes about 10 to 20%, namely 0.5 to 1 W, of the entirepower requirement. According to the present invention, the display unitemploys a memory effect display device provided with e.g. ferroelectricliquid crystal and thus, its power consumption will be minimized throughintermittent activation as well as the CPU.

[0098] As the result, the overall power consumption during mainly keyentry operation for e.g. word processing will be reduced to {fraction(1/100)} to {fraction (1/1000)}.

[0099] Embodiment 2

[0100]FIG. 9 is a block diagram showing a second embodiment of thepresent invention.

[0101] In the second embodiment, the first processor 4 is improved inthe operational capability and the second processor 7 of which energyrequirement is relatively great is reduced in the frequency of actuationso that energy saving can be encouraged.

[0102] As shown in FIG. 9, the arrangement of the second embodiment isdistinguished from that of the first embodiment by having a signal line97 for transmission of a display instruction signal from the firstprocessing block 1 to the display block 99. In operation, the firstprocessor 4 of the first processing block 1 delivers a display changesignal to the display circuit 8 of the display block 99 for change ofthe display text on the display 2. As understood, the second processor 7delivers such a display change signal to the display circuit 8 accordingto the first embodiment.

[0103]FIG. 10-a is a block diagram showing in more detail the connectionof the first processor 4, in which the first memory 5 comprises a firstfont ROM 40 for storage of dot patterns of alphabet and Japanesecharacter fonts or the like in a ROM, an image memory 41, and a generalmemory 42.

[0104] As shown in FIG. 11, the second memory 9 may contain a secondfont ROM 43 which serves as a font memory.

[0105] In operation, a series of simple actions for display text changecan be executed using the first processor 4. Character codes areproduced in response to the key entry and font patterns corresponding tothe character codes are read from the first 40 or second font memory 43for display on the display 2 after passing the display circuit 8. Thesecond memory 9 may also contain a second general memory 44.

[0106] During input of a series of data characters which requires nolarge scale of processing, the first processor 4 having less energyrequirement is actuated for operation of the display text change. Iflarge scale of processing is needed, the second processor 7 is thenutilized. Accordingly, the frequency of actuation of the secondprocessor 7 is minimized and energy saving will be guaranteed. Also, asshown in FIG. 11, the memory size of the first memory 5 can be decreasedbecause of retrieval of font patterns from the second font ROM 43 of thesecond memory 9.

[0107] The operation according to the second embodiment will now bedescribed in more detail referring to flow charts of FIGS. 11-a and11-b. FIG. 11-a is substantially similar to FIG. 6 which shows a flowchart in the first embodiment.

[0108] A difference is that as the first processor 4 directly actuatesthe display circuit 8, a step 130 and a display flow chart 131 areadded. When the first processor 4 judges that a desired data forreplacement in the display text is simple enough to be processed by thefirst processor 4 at Step 130, the procedure moves to the display flowchart 131. The display flow chart 131 will then be described briefly. Itstarts with Step 132 where the display block 99 is activated. At Step133, the display text is changed and the change is examined at Step 133.After the confirmation of the completion of the text change at Step 134,the display block 99 is de-energized at Step 135 and the procedurereturns back to Step 103 for stand-by for succeeding data input. FIG.11-b illustrates the step 133 in more detail. After the display block 99is activated, at Step 132, by a start instruction from the firstprocessing block 1, the movement of a cursor with no restriction isexamined at Step 140. If yes, data input throughout the cursor movementis executed at Step 141. If not, it is then examined whether the desiredinput area on the display 2 is occupied by existing data or not at Step142. This procedure can be carried out by reading the data in the imagememory 41 with the first processor 4. If no, partial text replacementwith desired data is executed at Step 143. If yes, the procedure movesto Step 144 where the existing data in the input area of the displayblock 99 is checked using the image memory 41 and examined whether it isnecessarily associated or not with the desired data to be input. If no,overwriting of the desired data is executed at Step 143. If yes, theexisting data is retrieved from the image memory 41 or read from thesecond font. ROM 9 and coupled with the desired data for composition, atStep 145. At Step 146, it is examined whether a black/white inversionmode is involved or not. If yes, the data is displayed in reverse colorat Step 147. If no, the text change with the composite data is carriedout at Step 148. Then, the completion of the text change is confirmed atStep 134 and the display block 99 is turned off at Step 99.

[0109] For more particular explanation, the processing action ofcorresponding components when the key entry is made is illustrated inFIG. 12. When the key entry with “I” is conducted at t₁ as shown in FIG.12-e, the first processor 4 shifts input data into a letter “I” code,reads a font pattern of the letter code from the first font ROM 40 shownin FIG. 10, and actuates the display circuit for display of the letter“I” on ,the display 2. With the memory effect display havingferroelectric crystal liquid, partial replacement in a character can bemade. The partial replacement is feasible in two different manners; onefor change dot by dot and the other for change of a vertical orhorizontal line of dots at once. The dot-by-dot change is executed withless energy requirement but at a higher voltage, thus resulting in highcost. The line change has to be done in the group of dots at once evenwhen one dot only is replaced but at relatively lower voltages. Both themanners in this embodiment will now be explained.

[0110] When the horizontal and vertical drivers 11, 12 shown in FIG. 3accept higher voltages, it is possible to fill the dots forming theletter “I” one by one. Accordingly, the letter “I” can be displayed byhaving a font data of a corresponding character pattern supplied fromthe first processor 4. However, ICs accepting such a high voltage arecostly. It is thus desired for cost saving that the operating voltage islow. It is now understood that every data processing apparatus ispreferably arranged, in view of capability of up-to-date semiconductors,for providing line-by-line text change operation.

[0111] It is also needed that the first memory 5 of the first processor4 carries at least data of one text line.

[0112] For Japanese characters, the one text line data is equal to640×24 dots. The writing of the letter “I” thus involves replacement of24 of 640-dot lines.

[0113] In operation, the previous data of a target line is retrievedfrom the image memory 41 of the first memory 5 and also, the patterndata of the letter “I” is read from the first font ROM 40. Then, the twodata are combined together to a composite data which is then fed to thedisplay circuit 8 for rewriting of one text line on the display 2.Simultaneously, the same data is stored into the image memory 41. Theinput of “I” is now completed.

[0114] Non of the first font ROM 40 and the image memory 41 is neededwhen the second font ROM 43 is employed for the same operation, which iscapable of processing coded data. In particular, the same text line canbe expressed with about 40 of 2-byte characters and thus, 40×2=80 bytesper line. Therefore, the first memory 5 may carry coded data of theentire screen image.

[0115] During the processing of data input “I” in either of the twoforegoing manners, the second processor 7 provides no processing actionas shown in FIG. 12-c.

[0116] Similarly, a series of key inputs are prosecuted by the firstprocessor 4, “space” at t₂, “L” at t₃, “i” at t₄“v” at t₅, and “e” att₆. Although the first processor 4 is much slower in the processingspeed than the second processor 7, the replacement of one text line ondisplay can be pursued at an acceptable speed with less energyconsumption.

[0117] As shown in FIG. 12, t₇ represents the key input of aninstruction for processing a large amount of data, e.g. spelling checkin word processing, translation from Japanese to English, conversion ofJapanese characters into Chinese characters, or calculation of chartdata.

[0118] When the first processor 4 determines that the processing at thesecond processor 7 is needed, the second processor 7 is turned on att₇₁. The start-up of the second processor 7 is the same as ofEmbodiment 1. As shown in FIG. 12-c, the second processor 7 upon beingactivated at t₇₁ returns to the original state prior to interruption andstarts processing the data of text lines fed from the first processor 4.As the processing is prosecuted, each character of changed text isdisplayed on the display 2 through the display circuit 8 as shown at t₇₂in FIG. 12-d.

[0119] This procedure will now be explained in the form of data entryfor translation from Japanese to English. After the letter k is input att₁, as shown in FIG. 12-f, and displayed on the screen, as shown in FIG.12-h. Then, the letter a is input at t₂ and the display reads “ka” asshown in FIG. 12-h.

[0120] By then, the second processor 7 remains inactivated as shown inFIG. 12-c. When a key of translating conversion is pressed at t₇, thesecond processor 7 starts processing at Accordingly, the Japaneseparagraph “kareha” is translated to “He is” in English. The resultantdata is sent to the display circuit 8 for dot-by-dot replacement fordisplay.

[0121] Now, the display reads “He is” as shown in FIG. 12-h. Thedot-by-dot character replacement shown in FIG. 12-g requires lesselectric energy than the text line replacement shown in FIG. 12-d.

[0122] For the purpose of saving energy during the movement of thecursor, the black/white inversion or negative mode is used as shown inFIGS. 13-a and 13-b. This however increases the power consumption in theline replacement. When a bar between the lines is used for display ofthe cursor as shown in FIGS. 13-c and 13-, the replacement of the fullline is not needed and thus, energy saving will be expected. Also, thespeed of processing is increased and the response will speed up duringprocessing with the low speed first processor 4. This advantage isequally undertaken in the dot-by-dot replacement.

[0123] As shown in FIG. 14-a, the movement of the cursor is expressed bythe bar. For ease of viewing, the bar may be lit at intervals by meansof control with the first processor 4. When a key data input is given, acorresponding character is displayed in the reverse color as shown inFIG. 14-b. This technique will also reduce the energy consumption atleast during the cursor movement.

[0124] FIGS. 14-a to 14-g illustrate the steps of display correspondingto t₁ to t₇. FIG. 14-h shows the conversion of the input text.

[0125] FIGS. 15-a to 15-f shows the insertion of a word duringdot-by-dot replacement. It is needed with the use of the second font ROM43 in the arrangement shown in FIG. 10 that the data of one text line issaved in the image memory 41 because the first font ROM 40 carries notall the Chinese characters. When the cursor moves backward as shown inFIGS. 15-c and 15-d, the letter n is called back from the image memory41. Accordingly, the data prior to insertion can be restored without theuse of the second processor 7 or the second front ROM 43 as shown inFIG. 15-d.

[0126] FIGS. 16-a to 16-g shows the copy of a sentence “He is a man”.The procedure from FIG. 16-a to FIG. 16-f can be carried out with thefirst processor 4. The step of FIG. 16-g involves an insertion actionwhich is executed by the second processor 7.

[0127] According to the second embodiment, most of the job which isprocessed by the second processor 7 in the first embodiment is executedby the low power consuming first processor 4. Thereby, the averageenergy consumption will be much lower than that of the first embodiment.

[0128] The optimum of a job sharing ratio between the first and secondprocessors 4 and 7 may vary depending on particulars of a program fore.g. word processing or chart calculation. Hence, a share of the firstprocessor 4 in operation of a software program can be controlled byadjustment on the program so as to give an optimum balance between theenergy consumption and the processing speed. Also, a video memory 82 maybe provided in the display block 99 for connection via a connecting line96 with the first processor 4. This allows the data prior to replacementto be stored in the video memory 82 and thus, the image memory 41 shownin FIG. 10-a will be eliminated.

[0129] Embodiment 3

[0130]FIG. 18 is a block diagram showing a third embodiment of thepresent invention. The difference of the third embodiment from the firstand second embodiments will then be described. As shown in FIG. 1, thefirst embodiment has the display start instruction line 81 along whichboth a start instruction and a stop instruction are transferred from thefirst processing block 1 to the display block 99 while equalinstructions are transferred by the start instruction line 80 from thesame to the second processing block 98.

[0131] The third embodiment contains no display start instruction line81 to the display block 99 as shown in FIG. 18. Also, the startinstruction line 80 of the third embodiment allows only a startinstruction but not a stop instruction to be transmitted from the firstprocessing block 1 to the second processing block 98.

[0132] The second processor 7 stops itself upon finishing the processingand enters into the energy saving mode. When the second processor 7determines that the display change is needed, it delivers an displaystart instruction via a data line 84 to the display block 99 which isthen activated. After the display change on the display 2 is completed,the display block 99 stops operation and enters into the display energysaving mode. This procedure will be explained in more detail using aflow chart of FIG. 19. The flow chart is consisted of a first processingstep group 151, a second processing step group 152, and a thirdprocessing step group 153. At first, the difference of this flow chartwill be described in respect to the sequence from start to stop of thesecond processing block 98.

[0133] There is no control flow from the second processing step group152 of the second processing block 98 to the first processing step,group 151, unlike the flow chart of the first embodiment shown in FIG.6. More specifically, the first processor 4 delivers out, at Step 112, astart instruction to the second processor 7 which is then activated.This step is equal to that of the first embodiment. However, the secondprocessor 7 is automatically inactivated at Step 121, as compared withde-energization by an instruction from the first processor 4 in thefirst embodiment. At Step 103, the second processor 7 is turned to adata input stand-by state.

[0134] The difference will further be described in respect to thesequence from start to stop of the display block 99.

[0135] In the first embodiment, a display start instruction to thedisplay block 99 is given by the second processor 7 after completion ofdisplay data processing. According to the third embodiment, The startinstruction is delivered by the second processing block 98 to thedisplay block 99, at Step 115 a shown in FIG. 19. Then, the displayblock 99 is activated at Step 116 and the display change is conducted atStep 117. After the display change is examined at Step 118, the displayblock 99, stops itself at Step 119.

[0136] As understood, the third embodiment which is similar in thefunction to the first embodiment provides the self-controlledde-energization of both the second processing block 98 and the displayblock 99.

[0137] Also, a start instruction to the display block 99 is given by thesecond processing block 98. Accordingly, the task of the firstprocessing block 1 is lessened, whereby the overall processing speedwill be increased and the arrangement itself will be facilitated.

[0138] Embodiment 4

[0139]FIG. 20 is a block diagram showing a fourth embodiment of thepresent invention, in which an energy saving manner is disclosed withthe use of an input/output port for communications with the outside. Adata processing apparatus of the fourth embodiment incorporates aninput/output unit 50 mounted in its data input block 97. Theinput/output unit 50 contains a communications port 51 and an externalinterface 52. In operation, the unit 50 performs actions as shown in atiming chart of FIG. 21 which is similar to the timing chart of key dataentry shown in FIG. 12. When a series of inputs from the communicationsport are introduced at t₁ to t₇₄, as shown in FIG. 21-a, theinput/output unit 50 delivers corresponding signals to the firstprocessing block 1. The first processor 4 sends an input data at t₁ tothe display circuit 8 which in turn actuates, as shown in FIG. 21-d, fordisplay of a data string as illustrated in FIG. 21-e. If an input at t₇is bulky, the second processor 7 is activated at t₇₁. as shown in FIG.21-c.

[0140] The second processor 7 delivers a start instruction at t₇₂ to thedisplay circuit 8 which is then actuated for data replacement on thedisplay 2. If the input through the communications port is not bulky, itis processed in the first processor 4 or the input/output unit 50 whilethe second processor 7 remains inactivated. Accordingly, energy savingduring the input and output action will be ensured.

[0141] Embodiment 5

[0142]FIG. 22 is a block diagram showing a fifth embodiment of thepresent invention, in which a solar battery 60 is added as an extrapower source. The first processor 4 operates at low speeds thusconsuming a small amount of electric energy. Accordingly, the apparatuscan be powered by the solar battery 60. While the action is almost equalto that of the first embodiment, the solar battery however stops powersupply when the amount of incident light is decreased considerably. Ifthe supply is stopped, it is shifted to from the source 61. When no keyentry is made throughout a length of time and no power supply from thesolar battery 60 is fed, the source stop mode is called for as shown inFIG. 23-b. The first processor 4 saves processing data into the firstmemory 5 and then, stops operation. Thus, the power consumption will bereduced. When a power supply from the solar battery 60 is fed again att₇ ₇₁ or another key input data is fed from the data input unit 3, thefirst processor 4 starts actuating for performance of an equal actionfrom t₇₂.

[0143] One example of the start procedure of the first processor 4 willnow be described. As shown in FIG. 24, a key input device 62 of the datainput unit 3 feeds a voltage from the battery 64 to a hold circuit 63.The hold circuit 63 upon pressing of a key connects the power source tothe first processor 4 for energization. Simultaneously, the key inputdevice 62 transfers a key input data to the first processor 4 andprocessing will start.

[0144] Each key of the key input device 62 may have a couple ofswitches; one for power supply and the other for data entry.

[0145] Accordingly, as the solar battery is equipped, the powerconsumption will be minimized and the operating life of the apparatuswill last much longer.

[0146] The solar battery 60, which becomes inactive when no incominglight falls, may be mounted on the same plane as of the display 2 sothat no display is made including text and keyboard when the solarbattery 60 is inactivated.

[0147] Hence, no particular trouble will arise in practice. In case ofword processing in the dark e.g. during projection of slide pictures ina lecture, a key entry action triggers the hold circuit 3 for actuationof the first processor 4.

[0148] As the data processing apparatus of the fifth embodiment providesmore energy saving, it may be realized in the form of a note-sizemicrocomputer featuring no battery replacement for years. Also, thefirst and second processors in any of the first to fifth embodiments maybe integrated to a single unit as shown in FIG. 25.

[0149] It was found through experiments of simulative calculationconducted by us that the average power consumption during a wordprocessing program was reduced from 5 w of a reference value to as smallas several hundredths of a watt when the present invention wasassociated with. This means that a conventional secondary cell lastshundreds of hours and a primary cell, e.g. a highly efficient lithiumcell, lasts more than 1000 hours. In other words, a note-size computerwill be available which lasts, like a pocket calculator, over one yearin use of 5-hour a day without replacement of batteries. As understood,intensive attempts at higher-speed operation and more-pixel display areconcurrently being prosecuted and also, troublesome recharging ofrechargeable batteries needs to be avoided. The present invention isintended to free note-size computers from tangling cords andtime-consuming rechargers.

[0150] The advantages of high speed and high resolution attributed toferroelectric liquid crystal materials have been known.

[0151] The present invention in particular focuses a more attention onthe energy saving effects of the ferroelectric liquid crystal which havebeen less regarded.

[0152] No such an approach has been made. The energy saving effects willsurely contribute to the low power requirements of portable dataprocessing apparatuses such as note-size computers.

[0153] Although the embodiments of the present invention employ adisplay device of ferroelectric liquid crystal for utilization of memoryeffects, other memory devices of smectic liquid crystal orelectrochromic material will be used with equal success. The liquidcrystal display is not limited to a matrix drive as described and may bedriven by a TFT drive system.

What is claimed is:
 1. A data processing apparatus comprising: a datainput unit for input of a data; a first processing unit for processingthe data inputted through the data input unit; a second processing unitfor processing an output data of the first processing unit; and adisplay unit for display of data processed at the first and/or secondprocessing units on a display device having a memory function, saidfirst processing unit having a means for selectively activating thesecond processing unit, which has been inactivated, according to datainput through the data input unit.
 2. A data processing apparatusaccording to claim 1, wherein the display device is a ferroelectricliquid crystal display device.
 3. A data processing apparatus accordingto claim 1, wherein the first processing unit has a means for detectingthat the processing of the second processing unit is completed andforcedly stopping the second processing unit.
 4. A data processingapparatus according to claim 1, wherein the first processing unit has ameans for driving the display unit.
 5. A data processing apparatusaccording to claim 1, wherein the second processing unit has a means forgeneration of a display start signal which instructs the firstprocessing unit to start driving the display unit.
 6. A data processingapparatus according to claim 1, wherein the second processing unit has ameans for driving the display unit.
 7. A data processing apparatusaccording to claim 1, wherein the second processing unit has a means forstopping itself upon completion of its own processing action.
 8. A dataprocessing apparatus according to claim 7, wherein the second processingunit has a means for driving the display unit.
 9. A data processingapparatus according to claim 8, wherein the second processing unit has ameans for stopping itself upon completion of driving the display unit.10. A data processing apparatus according to claim 1, wherein the firstprocessing unit has a means for driving the display unit and a means fordelivering a display data to the display unit for change of a displaystate of the display unit.
 11. A data processing apparatus according toclaim 10, wherein the second processing unit has a means for driving thedisplay unit.
 12. A data processing apparatus according to claim 10,wherein the first processing unit has a means for storage of a portionof a display data of the display unit.
 13. A data processing apparatuscomprising: a data input unit for input of a data; a first processingunit for processing the data inputted through the data input unit; asecond processing unit for processing an input data of the firstprocessing unit; and a display unit having a memory-effect displaydevice for display of data processed at the first and/or secondprocessing units, said first or second processing unit having a meansfor driving the display unit.
 14. A data processing apparatus accordingto claim 13, wherein the first processing unit has a means foractivating and/or inactivating the display unit.
 15. A data processingapparatus according to claim 13, wherein the display unit has a meansfor inactivating itself upon completion of its display action.
 16. Adata processing apparatus according to claim 13, wherein the secondprocessing unit has a means for activating and/or inactivating thedisplay unit.
 17. A data processing apparatus according to claim 1,wherein the data input unit has at least a keyboard of which inputsignal is converted by the first processing unit to a input code signaland the second processing unit has a start device remaining activateduninterruptedly and a CPU arranged for intermittent activation so that,in operation, when receiving the input code signal, the start deviceactuates the CPU to commence processing a program and subsequently, theCPU after completion of a desired processing action stops processing theprogram at a keyboard input stand-by state with its clock turned offwhile saving a corresponding data in its internal register and starts itagain from its keyboard input stand-by state when activated by the startdevice.
 18. A data processing apparatus according to claim 1, whereinthe second processing unit has a CPU chip containing a register and aninternal memory so that it can stop upon disconnection of a CPU clocksignal with both the register and the internal memory saving data andstart again when the clock signal is released.